Various types of filtration apparatus have been in use for some time. Gooch or Buchner funnels which use circular filter elements made of glass or cellulosic fibers that are held flat against the perforations of the funnel are well known. Further, British Pat. No. 1,351,752 discloses a unitary disposable filtration apparatus which comprises a filter element, a molded plastic tubular holder having a flow passage therethrough, a molded plastic support holder in which the support member extends across the inside of the holder to support the filter element across the flow passage of the holder during filtration, and sealing means which interlock the support member to maintain pressure on the outer periphery of the filter element. A filter element is locked in position across the flow passage of the holder adjacent to the support member. Although the apparatus of the patent gives satisfactory results, it does not provide for rapid and simultaneous treatment of a plurality of samples.
Other apparatus are commercially known including those for use in biochemical filtration or sample testing applications, but such devices are relatively complex leading to relatively high costs and are cumbersome or inconvenient for use.